1. Field of the Invention
This invention is directed to seals between interfacing apparatuses; to lubricating oil flow path seals; and, in certain particular aspects, to seals for inhibiting lubricating oil flow from a top drive gear system to a top drive motor.
2. Description of Related Art
The prior art discloses a variety of top drive systems; for example, and not by way of limitation, the following U.S. Patents present exemplary top drive systems and components thereof: U.S. Pat. Nos. 4,458,768; 4,807,890; 4,984,641; 5,433,279; 6,276,450; 4,813,493; 6,705,405; 4,800,968; 4,878,546; 4,872,577; 4,753,300; 6,007,105; 6,536,520; 6,679,333; 6,923,254—all these patents incorporated fully herein for all purposes.
Certain typical prior art top drive drilling systems have a derrick supporting a top drive which rotates tubulars, e.g., drill pipe. The top drive is supported from a travelling block beneath a crown block. A drawworks on a rig floor raises and lowers the top drive. The top drive moves on a guide track.
In many typical prior art top drive systems the top drive includes a motor which meshes with and drives a gear system below the motor to drive a drive shaft for drilling and other operations. Lubricating oil lubricates and is maintained in the gear system. A seal, seal assembly, or seals selectively prevent the gear lubricating oil from flowing from the gear system to a space or cavity below the motor, to the motor shaft, and to the motor. In the past metal-to-metal seals have been used to close off this flow path; but, especially with higher and higher top drive gear speeds, metal-to-metal seals can wear relatively quickly. Also, many metal-to-metal seals require that a flat surface on a seal sealingly contact a flat surface of another member to effect a good seal.